1. Field of the Invention
The present invention relates to a blower which is mounted to home appliances such as an air conditioner, vacuum cleaner, etc, in order to suck and discharge air. More particularly, the present invention relates to a blower which is equipped with a turbo fan installed at the interior of a scroll housing thereof, while enlarging the angle of inclination of a cutoff of the scroll housing, thereby enhancing blowing performance and reducing noise of the blower.
2. Description of the Related Art
As well known to those skilled in the art, a blower generally includes an impeller 1, so called a xe2x80x9csirocco fanxe2x80x9d, and a scroll housing 2 adapted to guide air sucked by the impeller 1, thereby discharging the sucked air through an outlet 26, as shown in FIGS. 1 and 2.
The impeller 1 includes a plurality of blades 1a supported by a rib 1b. The impeller 1 has a shaft 11 connected to the drive unit of a motor M. When the impeller 1 is rotated in accordance with an operation of the motor M, air is sucked into the interior of the scroll housing 2 through a sucking inlet 24 formed at the front end of the scroll housing 2 while being guided by a bell mouth 25. The sucked air is then fed along a gradually-enlarged passage to the outlet 26, and then outwardly discharged through the outlet 26.
The scroll housing 2 includes a body portion 2a having a substantially cylindrical shape while receiving the impeller 1. The body portion 2a serves to guide air sucked through the sucking inlet 24 in a rotating direction of the impeller 1. The scroll housing 2 also includes a hopper portion 2b extending upwardly from the body portion 2a. The hopper portion 2b serves to discharge the air introduced into the body portion 2a through the outlet 26.
The scroll housing 2 is constructed by a front panel 21 defined with the sucking inlet 24, a rear panel 22 spaced apart from the front panel 21 by a desired distance, and side panels 23 for sealing all edges of the front and rear panels 21 and 22, except for the outlet 26.
The hopper portion 2b has a right wall 23a extending vertically from the body portion 2a, and a left wall 23b extending inclinedly from the body portion 2a in such a fashion that the hopper portion 2b has a cross-sectional area gradually enlarged toward the outlet 26. That is, a cutoff 3 having a concave structure is formed between the body portion 2a and the hopper portion 2b. 
The cutoff 3 extends from its cutoff portion 31 on the front panel 21 to it cutoff portion 32 on the rear panel 22 while being inclined with respect to the shaft 11 of the impeller 1 by an angle of xcex81. Typically, the inclination angle xcex81 of the cutoff 3 is 50xc2x0 or less. Air discharged from the body portion 2a is guided along a flow passage defined by the hopper portion 2b to have a gradually-enlarged cross-sectional area from the cutoff 3, so that it is discharged from the outlet 26 in a state in which its pressure is converted from dynamic pressure into static pressure at the outlet 26.
However, the above mentioned conventional blower has a limitation in increasing the amount of blown air because the impeller 1 called a xe2x80x9csirocco fanxe2x80x9d is installed in the interior of the scroll housing 2. Furthermore, the inclination angle xcex81 of the cutoff 3 formed at the scroll housing 2 is 50xc2x0 or less with respect to the shaft 11 of the impeller 1. As a result, there is a problem in that flow resistance of air passing through the hopper portion 2b is increased, thereby degrading the blowing efficiency of the blower while increasing generation of noise.
Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a blower which is capable of increasing the flow rate of blown air while minimizing the flow resistance of air being discharged, thereby achieving an improvement in blowing efficiency.
It is another object of the present invention to provide a blower which is capable of reducing generation of noise.
In accordance with the present invention, these objects are accomplished by providing a blower including a motor, a blowing fan coupled to the motor via a shaft, and a scroll housing including a front panel having a sucking inlet, a rear panel, and side panels sealing all edges of the front and rear panels, except for the outlet, the scroll housing defining a body portion serving to guide air sucked through the sucking inlet in a rotating direction of the blowing fan, a hopper portion extending from the body portion while serving to discharge the air introduced into the body portion through the outlet, and a cutoff formed at a boundary between the body and hopper portions to extend the front panel to the rear panel, wherein the cutoff of the scroll housing has an inclination of 50 to 80xc2x0 with respect to the shaft of the blowing fan.
Preferably, the inclination of the cutoff is ranged from 60xc2x0 to 70xc2x0.
Preferably, the blowing fan is a turbo fan in accordance with the present invention.